Image sensor and method for manufacturing the same

Abstract

An image sensor and a method for manufacturing the same are provided. A photodiode region and transistor region are vertically-integrated to improve the fill factor and resolution of the image sensor. Unit pixels can be isolated by a metal isolation layer arranged between adjacent photodiode areas.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]The present application claims the benefit under 35 U.S.C. §119 of Korean Patent Application No. 10-2007-0037357, filed Apr. 17, 2007, which is hereby incorporated by reference in its entirety.BACKGROUND[0002]In general, an image sensor is a semiconductor device for converting optical images into electrical signals, and is mainly classified as a charge coupled device (CCD) or a Complementary Metal Oxide Silicon (CMOS) image sensor.[0003]A CMOS image sensor sequentially detects electrical signals of pixels in a switching scheme by forming photodiodes and MOS transistors in unit pixels.[0004]A CMOS image sensor is simpler in a driving scheme than compared to a CCD image sensor. It is also capable of implementing a variety of scanning schemes and integrates signal processing in a single chip so that miniaturizing a product is possible. A CMOS image sensor uses CMOS technology so that manufacturing costs and power consumption are low.[0005]A C...

AI Technical Summary

Benefits of technology

[0010]Furthermore, according to the horizontal-type CMOS image sensor, additional on-chip functions are added to the image sensor so that the sizes of unit pixels are increased or reduced in order to maintain the sensitivity of the image sensor.

Problems solved by technology

While the horizontal-type CMOS image sensor improves upon some of the disadvantages of the CCD image sensor, problems still exist in the horizontal-type image sensor.

Thus, the photodiode cannot encompass the entire area of a pixel region of the image sensor, leading to a reduced fill factor and / or limited resolution.

In addition, with a horizontal-type image sensor, it is very difficult to achieve optimization for the process of simultaneously manufacturing the photodiode and the transistor.

A shallow junction is required for a low sheet resistance in a rapid transistor process, but the shallow junction may not be appropriate for the photodiode.

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